National Wildlife Refuge Heron Flats Trail

U.S. Fish & Wildlife Service

Aransas

National Wildlife Refuge
Heron Flats Trail

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Welcome to the Welcome to the Heron Flats Trail.
Heron Flats Trail Here you can look for the native
plants and get an overview of the
1 area from the observation platform.
This trail takes you along a series
Mesquite of ancient oyster shell ridges that
border the salt marsh.
2 Learn to recognize mesquite (“muh-
SKEET”); it occurs all across Texas.
Salt Cedar Lacy leaves throw a dappled shade,
and long brown pods yield beans
3 relished by coyotes and javelinas.
Across the slough you can see the
Cordgrass pendulous, light green foliage of a
dense clump of salt cedar. These
4 natives of Asia, introduced into this
country for windbreaks, have spread
into low-lying areas and along bay
shores throughout the Coastal Bend.
The thick mat of grass with a cowlick
profile in the slough is marshhay
cordgrass. On the other side of the
trail, Gulf cordgrass grows in robust,
waist-high clumps.

Groundsels The several spindly trees here are
groundsels. Few trees can withstand
5 the rigors at the edge of the salt
marsh, but groundsel manages. Look
Saltmarsh at the oyster shell ridge beyond
Bulrush the slough to see what a difference
elevation makes. None of the plants
6 on the ridge can survive where the
groundsels reign.
The grass-like plants bordering the
marsh are saltmarsh bulrush. Here
you have a look at the many other
salt-adapted plants in the marsh and
the dense growth of woody plants
(collectively called “chaparral”) that
caps a mound of shell on the edge of
San Antonio Bay.

“Pricklies” Here is an assortment of “pricklies”—
the cactus is Texas prickly pear.
7 Behind it is a fierce-leaved Spanish
dagger. Nearby find a shrubby
agarito with leaf margins extended
into sharp points.

Spanish Dagger Another Spanish dagger. Don’t
get too close; those stiff leaves are
8 dangerously sharp tipped! Large
candelabras of waxy white flowers in
early spring yield finger-sized woody
fruits chock full of flat black seeds.

Netleaf Hackberry These two gangly netleaf hackberry
trees are probably not happy here on
9 the edge of the salt marsh. You will
see much finer examples on higher
ground. Touch the upper side of a
leaf from tip to base to feel the sand-
papery texture.

Mexican Many birds and mammals eat the
Persimmon sweet, marble-sized black fruits of
Mexican persimmon. Feel its smooth
10 branches and notice the tufts and
swirls of gray-green lichens (“LIKE-
ens”) that decorate the limbs.

Common Reed Common reed is a gigantic grass that
grows along sloughs and bay shores.
11 The Karankawa Indians who once
roamed this area used sections of this
cane to fashion arrow shafts.

Mustang Grape You have just left the lower outer
oyster shell ridge and are beginning
12 the center, higher and drier one.
The heavy woody vine scrambling
among the shrubs is mustang grape.
It is very common on the refuge and
usually produces a bountiful crop of
purple grapes. Birds and mammals
swallow them whole, enjoying the
sweet pulp underneath the acrid
tasting skin.

Lime Prickly Ash You can recognize lime prickly ash
by catclaw prickles, scalloped-edged
13 leaflets, and the strong citrus smell of
its foliage. Crush a green snippet and
inhale the stimulating aroma.

Netleaf This great, gnarled tree is a netleaf
Hackberry/Texas hackberry. Compare it to the anemic
Torchwood hackberries near the salt marsh. The
dark green shrub with crinkly-edged
14 leaves is Texas torchwood, so called
because it contains oils that cause it
to burn readily. It is living near the
northern edge of its range here.

Tanglewood Tanglewood forms thornless walls of
interlocking zig-zag branches along
15 much of this trail. Early in February,
while most other plants are still
Pearl Milkweed winter dormant, tiny greenish-yellow
Vine flowers with sprays of red anthers
erupt along its bare branches.
16 Look for a vine with paired, heart-
shaped leaves. You might find its
flower—pale green with a pearly spot
in the center. This is pearl milkweed
vine. In late summer its spindle-
shaped pods open to release fine
bristly puffs that parachute the seeds
away on the coastal breeze.

Turk’s Cap If the Turk’s cap here bear their waxy
red flowers or flattened apple-like
17 fruits, you can’t miss them. Look
for thigh-high plants with broad
rounded leaves with all the main veins
radiating from their base. The flowers
are attractive to hummingbirds and
butterflies.

Coast Live Oaks You have just crossed Cattail Slough
and gained the third shell ridge. Sit
18 on the bench awhile in the shade of
a fine grove of coast live oaks. The
soil here is dark and rich and covered
by thick litter of decaying leaves, a
more protected habitat than the open,
younger ridges. If you missed Turk’s
caps at the previous station, try again
here.

Tree Huggers Look up into the dead live oak tree
arching over the trail. Can you find
19 two different plants growing on its
branches? Ball moss clings tightly in
gray tufts; Spanish moss hangs down
in thick festoons. Both of these plants
produce flowers, so neither is a “true
moss.” Greenbriar, a vine with green,
thorny stems, occurs here and along
the remainder of the trail.

Mexican Buckeye The shade-loving Mexican buckeye
has multiple stems and large
20 compound leaves with lance-shaped
leaflets. It is decked with delicate
pink flowers in early spring and
produces three-lobed, brown seed
capsules in summer. The marble-sized
black seeds that fall from the capsules
are poisonous to people. (Drawing on
front cover.)

Dwarf Palmetto There are two native palms in the
state of Texas; the dwarf palmetto is
21 one of them. You can’t miss its stiff,
dark green, fan-shaped leaves. In
summer this plant sends up a wand of
small papery flowers that transforms
into clusters of bun-shaped black
fruits; their sweet dry pulp is favored
by many kinds of wildlife.

True Moss The craggy bark on this storm-
tossed coast live oak is covered with
22 a luxuriant carpet of true moss,
a primitive plant that reproduces
by spores rather than by flowers
and seeds. Moss can withstand dry
conditions, but it will be at its finest
with frequent rain showers. Notice
the thick brown vine growing up this
tree; look up for the bright orange
funnel-shaped flowers of trumpet
creeper.

Black Willow This granddaddy black willow has
gotten so large that its limbs are
23 breaking from their own massive
weight. A thicket of more normal-
Yaupon sized willows lines the edges of
Thomas Slough.
24 Migrating robins and resident
mockingbirds compete for the bounty
of red berries produced by yaupon
(YO-pahn) each autumn. One of the
most common “understory shrubs”
(those living in the shade beneath
trees) on the refuge, it is growing
here in a grove of hurricane-ravaged
coast live oaks.

Scrambling Vines Close out your walk with a couple of
scrambling vines. This patch is mostly
25 composed of pepper-vine, with glossy,
dark green leaves and grape-like
fruits that change from lilac to purple
as they mature. Woven through the
pepper-vine are prickly stems of
dewberry. In early spring dewberries
sport bright white flowers; by
late spring a variety of birds and
mammals gobble up the sweet black
berries.





Aransas National Wildlife Refuge
P.O. Box 100
Austwell, Texas 79950
361/286-3559/3533
361/286-3722 Fax
361/286-3409 TDD
http://southwest.fws.gov
U.S. Fish & Wildlife Service
www.fws.gov/southwest/refuges/tx
For Refuge Information
1 800/344-WILD
Funding for this brochure provided by proceeds
from entrance fees.
August 1999

Cover artwork of Mexican buckeye and all other
artwork by Wayne H. and Martha K. McAlister